Hi.
I'm trying to help my friend get his 2003 Polaris 250 Trailblazer running.
I think the piston rings are not seated properly because the engine only has 45lbs of compression. When I slowly turn the engine over by hand, I can hear compression leaking back thru the carb just before the piston hits TDC.
Last year he paid a local shop $800.00 to rebuild the top end and only took the bike out twice before it died again.

Where is the best place to buy a set of rings & gaskets?


Thanks for any advice you can give me.

Tim

 

let us know what you find when you get it apart

 

Well I removed the cylinder and found 2 large grooves in the sides of the piston and some aluminum shavings laying around the crankshaft area. I need pull the rest of the engine apart so I can get all the aluminum shavings out. The cylinder walls don't appear to have any damage but I'm assuming I should probably have it bored out? Does anyone know how much that typically costs? The engine has never been bored before and my friend would like the bike to have more power.. so I'm wondering what's the biggest piston I can use without making it undependable?
Also... Does anyone know of a good machine shop in the Phoenix area that can bore this out?

Thank you,
Tim

 

"Last year he paid a local shop $800.00 to rebuild the top end and only took the bike out twice before it died again."
what did they do if they rebuilt the top end?? a rebuild or a freshen up of the top is usualy a boring of the cylinder if it is worn enough or at least a good honing out w/ new rings. i would want to find out what they did for sure for $800 as that should have been new piston,rings and a boring of the cyl. for sure. you need to find out what caused the scratches and where the shaving came from. did the shop make a mistake when they reassembled it? either way if your going to put more work into this engine i would contact rick ritter(rcr racing) who has a web site and is real good on these 2 strokes and making power and see what he suggest. imo

 

My friend just found his receipt and it looks like they did bore the engine and replace the piston.

Does anyone know what the stock diameter of the cylinder is?
I need to make sure they actually did the work that he was charged for.

 

not sure onthe size, but you need to find what caused the marks/shavings and maybe take it back to the shop who fixed it to say hey why did this do this?? did the clip come out of the piston and scratch the walls, did the rings break or get put in wrong? no way should anything have happened that quick. imo

 

not for sure if the 2003 piston is the same as the 1 they used in the 2000 model, but the stock size piston for my 2000 trailblazer is a 72mm.

 

They are the same! Hopefully he's got it repaired by now! OPT